Safety seal packer



Jan. 17, 1967 D. E. YOUNG 3,298,441

SAFETY SEAL PACKER Jan. 1 7, 1,967 l D, YOUNG 3,298,441

SAFETY SEAL PCKER Filed March 11, 1964 s sheets-sheet e 1967 D` E; YOUNG SAFETY SEAL PACKER 3 Sheets-Sheet 5 Filed Marh 11, 1964 awa/ V0 any.

` INVENTOR.

United States Patent O 3,298,441 SAFETY SEAL PACKER David E. Young, Bellaire, Tex., 'assignor to Schlumberger Well Surveying Corporation, Houston, Tex., a corporation of Texas Filed Mar. 11, 1964, Ser. No. 351,025 9 Claims. (Cl. 166-179) This invention relates to a well tool control and more particularly to an apparatus for selectively controlling the relative movement between telescoping members of a well tool.

Commonly, in formation testing of wells, packers are included in a string of formation testing tools to isolate a section or formation to be tested from another part of the well bore. A typical packer well tool is comprised of an elastomer packer element positioned between flanges on telescoping members. By providing relative movement between such telescoping members, the ilanges can be moved toward one another lto compress and expand the elastomer element between the flanges to seal olf the well bore. Subsequent to this setting of the packer, it may be desirable to utilize additional longitudinal move` ment for other tools a-ttached to the packer to perform other operations or tests in the well bore. In many instances, the subsequent longitudinal movement of the tool string will permit the flanges on the packers to move relative to one another so that a premature contraction of the packer element in the well bore occurs and terminates the sealed-olf condition in the well bore.

It is therefore an object of the present invention to provide apparatus for selectively controlling the relative position of telescoping members in a well packer.

vAnother object of this invention is to provide -an appar-atus for releasably retarding relative movement between telescoping members of a well tool wherein the retarding apparatus is selectively controlled by a quick moti-on transmitted to one of the members to permit relative movement of the telescoping members.

Yet another object of this invention is to provide a releasable hydraulic means for retarding the relative movement of telescoping members of a well tool wherein said apparatus is responsive to rapid movement of one of the members to release the retarding apparatus.

A still further object of this invention is to provide an apparatus for maintaining telescoping members of a packer in a contracted position while longitudinal movement of tools attached to the packer may be utilized to operate the tools.

With these and other objects in view, the present invention contemplates an apparatus which may be formed as an integral part of a packer or which may be provided as an adapter section for a conventional packer wherein telescoping members of the packer may be releasably locked in a contracted position. More particularly, the apparatus includes an annular chamber formed between the telescoping members (of a well tool) and avpiston formed on one of the members for sliding within the chamber. Passageways through the piston provide for communication and transfer of iluid so that the piston can move relative to the chamber. A valve control means is formed in the piston intermediate the ends of the passageways. The valve control is normally -operative to close the passageways and thereby block communication through the piston. The valve control is, however, responsive to a slight relative movement between the telescoping members to open the passageway to fluid cornmunication for a determinable period of time thereby permitting movement of the piston within the chamber and relative movement between the telescoping members.

A complete understanding of this invention may be had by reference to the following detailed description 31,298 ,441 Patented Jan. 17, 1967 when read in conjunction with the accompanying drawings illustrating an embodiment thereof, wherein:

FIG. 1 is a schematic View of a string of well tools positioned in a well bore;

FIGS. 2a and 2b are detailed vertical sections of a well tool control embodying the present invention;

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 2a showing the valve control in detail;

FIG. 4 is a view along line 4 4 of FIG. 3; and

FIGS. 5 to 8 are detailed views of another control device shown in various stages of operation.

Referring first to FIG. l, a string :of well tools 11 is .shown suspended from a string of pipe 12. The string of tools includes, for example, a tester 16, a by-pass 17 and a packer 18. A safety seal section 19 embodying the present invention is connected to the packer 18. The tester may be of the type set forth in Patent No. 3,065,.-` 796. The packer 18 is of conventional construction and includes an expandible packer element 22, upper and lower anchoring means 23 and wall-engaging friction pads 24. The by-pass 17 is likewise of conventional construction and capable of being held closed while longitudinal forces -are applied to the string of tools.

Referring to FIGS. 2a and 2b, safety seal `section 19 includes a tubular mandrel 27 telescopically received within a tubular housing 28, the mandrel and housing respectively being adapted at their upper ends for connection to the mandrel and housing of a packer section po- .sitioned Iabove the safety seal section. The mandrel 27 has upper and lower enlarged portions 38 and 37, respectively, each having a ysimilar diameter and are slidably and sealingly received within the bore of the housing 28. O-rings 35 and 36 are disposed between the enlarged portions and the housing bore to provide la fluidtight seal. These are ring seals formed in the upper and lower ends of an annular space between the mandrel and housing which forms a chamber 29 for receiving a hydraulic iiuid. An annular piston 41 is xed in position on the mandrel intermediate =of the seals and is slidably received within the chamber 29. The housing bore has step-recessed portions, an upper bore portion 32 being enlarged greater than a lower bore portion 33. A seal member 43 on the piston provides a iluid-tight seal when the seal member 43 and piston 41 are within the lower portion 33 -of the chamber 29. When the seal 43 is positioned in the enlarged bore portion 32 `of the chamber, it has no sealing function. When the seal 43 on the piston is sealingly received in the lower bore portion 33, it separates chamber 29 into upper and lower chamber portions 54 and 53, respectively.

The details of piston 41 on the mandrel will be best understood by reference to FIGS. 2a, 3 and 4. In FIGS. 3 and 4 the piston 41 has a first passage 51 extending from the top surface of the piston to the lower piston surface comprised of an upper ow conduit 51a and a lower flow conduit 51b which are selectively coupled to one another via a valve chamber 56 in the piston 41. Upper conduit 51a has a one-way, spring-biased ball valve arranged to permit fluid in chamber 2-9 to pass through the piston from the upper chamber portion to the lower chamber portion.

The pist-on also has a second passage 52 extending from the bottom surface of the piston to its outer circumferential surface at a point above seal 43 and is comprised of a lower ow conduit 52b and a traverse conduit 52a which are selectively coupled to one another via the valve chamber 56. The traverse conduit 52a opens to a relieved portion of the piston 411 above seal 43 so that the second passageway eifectively couples the upper and lower chamber portions S4 and 53 to chamber 29 to pass through the piston from the lower chamber portion 53 to the upper chamber portion 54.

Valve chamber 56 is a longitudinally-extending bore opening at its lower end to conduit 521; which has a smaller diameter. In the valve chamber 56 is a spool valve member 63 having upper and lower valve portions 64 and 65 which are separated by a recessed by-pass portion 68 formed on the spool valve. Valve portions 64 and 65 are sized relative to the chamber to permit a relatively low rate leakage of fluid around the valve portions. The valve member 63 is biased by a spring 67 in the piston toward a position where the second passage 52 is closed.

l In the position of valve member 63y illustrated in FIG. 4, the spring 67 is -compressed and both the passages 51 and 52 are open. Upper conduit 51a has its opening 62 to valve cylinder 56 located so that when the valve member is in its lower position closing passage 52, the opening 62 is closed. Opening 61 of lower conduit 51h is, however, located relative to valve cylinder S6 so that when the valve member 63 is in the lower position, the conduit 51b is opened to the recess in the valve member. Openings 58 and S7 provide communication between the valve cylinder 56 and the upper and `lower flow conduits 52a and 52b and when the spool valve 63 is in its lower position, -both the ports or openings 58 and 57 are closed.

Referring now to FIG. 2, longitudinal internal annular cavity 73 is in the wall of the mandrel 27 below the mandrel piston 41. A port 74 at the upper end of the internal cavity 73 fluidly connects the cavity and the lower chamber portion 53. A passageway 77 extends lfrom the lower end of the cavity to the exterior of the mandrel to provide a fluid communication path between the cavity and the exterior of the well tool. A compensating piston 78 is slidably and sealingly received within the cavity and a spring 79 is positioned below the compensating :piston in the cavity to provide an upward bias of the piston in the cavity. Piston 78 pressure-balances the fluid in the chamber relative to the pressure of the fluid exterior of the tool.

In the operation of the apparatus shown in FIGS. l to 4, a downward movement on the packer mandrel is used to set the packer after the packer housing has been anchored to the casing by the packer friction pads 24 and slips 23. Relative movement between the packer and safety seal mandrel and housing is prevented while the tools are being lowered in the casing by a pin and I-slot arrangement 82 between the mandrel and housing of the packer. This pin and I-slot arrangement may be alternatively provided on the safety seal section 19. In order to unjay the mandrel and housing members for relative longitudinal movement, the pin is moved relative to the slot by an upward movement from the mandrel and rotation of the mandrel (by the string of pipe) to t-he right to position the pin in a long part 83 of the slot as shown in FIG. l, and downward movement of the packer mandrel relative to the housing (held stationary by the friction blocks). The housing is restrained from movement by the friction pads 24 in friction engagement with the well casing. After unjaying the housing and mandrel, the downward movement causes the expanders to radially extend the slips 23 into anchoring engagement with the casing. Further downward movement of the packer mandrel compresses and expands packer element 22 to pack off the well bore.

The relative movement between the packer mandrel and housing to set the packer also occurs in the att-ached mandrel 27 and housing 28 of the safety seal section 19. Upon downward movement of the safety seal mandrel with respect to the stationary housing, the mandrel piston 41 (see FIG. 4) is moved downwardly in the fluid-filled chamber 29 and fluid is freely transferred from the lower chamber portion 53 to the upper chamber poltion 54 via the passageway and also around the piston until the seal 34 is received in the restricted bore portion 33. Specically, in passage 52 the ow goes through the check valve 71 in conduit 52b and acts on the lower end of valve element 63 to displace it while compressing spring 67. The displacement of valve element 63 permits fluid communication between the cylinder ports 57 and 58 and transverse conduit 52a. As the mandrel moves downwardly with respect to the housing, the seal lring 43 formed on the mandrel piston engages a wall of restricted portion 33 of the chamber, forming a seal therebetween. After the packer element has been expanded in the casing and relative movement between the mandrel and housing stops, a -iluid is no longer forced to flow through the check valve 71 and first passageway 52 from the lower chamber 53 to the upper chamber 54. At this time t-he pressure in the upper and lower chamber portions is equalized and the biased check valve 71 closes. The compressed spring 67 positioned above the spool control valve 63 now operates to move the control valve to its lowermost position at a rate controlled by displacement of fluid between the valve cylinder and lower valve portion 65.

After a period of time, the valve moves to its lowermost position and closes ports 57, 58 and 62 and therefore prevents fluid communication in either direction through the passageways 52, 51. While moving downward, the valve member rst closes off ports 57, 58 and then port 62, with port 61 remaining open to the recess 68 of the valve member. With the valve ports in this latter condition, relative movement between the safety seal packer mandrel and housing is prevented because diuid can not be transferred through passages 511, 52. Since the packer is expanded in the casing, the safety seal section will hold it expanded by preventing relative longitudinal movement.

In order to effectuate a selective release of the safety seal mechanism to permit relative movement between the mandrel and housing members yof the safety seal and packer, and thereby permit release of the packer element 22, rst an upward force or pull is applied to the mandrel 27 and then the force is released, which applies `a downward force to the mandrel to thereby move the mandrel a short distance downwardly. Alternatively, downward force can be quickly applied to the mandrel. In either case, during the short downward movement =of the mandrel and piston 41, a relatively large pressure is generated in the lower port or chamber 53 which displaces the ball in the check valve 71 positioned in the lower portion 5211 of the rst passageway and acts on the relatively small area on the lower face of the spool piston 63. This pressure quickly displaces the spool piston 63 to a position opening the ports 57, 58 and 62 of the rst 4and second passageways thereby providing iiuid communication from one end of the passageways to the other. Before the spool valve can reset in its downward position under the faction of the weak valve spring 67, enough time lapses to permit movement of the mandrel piston 41 in the fluid chamber 29 to bring seal 43 into recess portion 32 and `also unseat the packer. Fluid flow then occurs, during this time lapse, through the second passageway 51 from the upper end 54 of the chamber to the lower end 53 through the ports 61 and 62 in the valve cylinder permitting free movement of tihe piston 41 in the fluid chamber and consequently movement of the mandrel 27 upwardly relative to the housing 28. This relative movement permits release of the packer element 22 from its packed-011r condition. The time lapse required for the spool valve 63 to move to its downward position is controlled by the relative size of the valve in the cylinder since fluid must be displaced around the spool valve in order for the valve to seat over ports 57 and 58 under the action of the valve spring.

In the event that the -spool valve 63 should fail to move upwardly in response to quick downward movement of the mandrel to open the ports to iluid communication, the sizing of spool valve 63 in the cylinder 56 permits a restricted flow of fluid around the valve by the application of an upward force on the mandrel. This safety feature provides for the restricted flow of fluid around the spool valve from port 62 to 61. The upward force will eventually cause enough fluid to displace through the restricted opening to move the mandrel upwardly a distance sufficient to permit release of the packer element. The time required to effect this safety release is, of course, dependent upon the spool valve size with respect to the cylinder.

The port 61 communicating with the lower portion 5111 of the second passageway is offset downwardly fnom a point opposite the port 62 of the upper portion 51a and is therefore always exposed to the recessed portion 68 of the spool valve to remain open regardless of the position of the spool valve. This offset relation prevents pressure on the spool valve from shifting the spool valve against the port 61 to close off the port from the restricted fluid flow in emergency conditions described above.

The compensating pist-on 78 (FIG. 2) which is positioned in the cavity 73 of the mandrel and communicates wit-h the lower end 53 of the fluid chamber, is provided to maintain a constant volume in the fluid chamber regardless of temperature chan-ges within the well bore.

Another arrangement of the safety seal apparatus is shown in FIGS. 5-8. A safety seal mandrel 84 is shown telescopically received within a safety seal housing mem- Iber 86 and an annular chamber 87 is formed between the h-ousing member and mandrel to receive a fluid. A pressure compensating piston 92 backed by a spring 93 is positioned at a lower end 94 of the chamber, with the lower end of the compensating piston in fluid communication with the outside of the tool through a port 96 formed in the lower end of the housing. An O-ring 97 is positioned on the compensating piston to provide a fluid tight seal for the lower end of the fluid chamber 87. The upper end of the chamber is closed by an O-ring in an inwardly-extending housing flange 100.

A piston assembly 98 has an upper pist-on portion 102 with an O-ring seal slidably and se-alingly received in an upper bore portion 89 4of the housing. This O-ring seal on the upper piston portion 102 separates the chamber 87 into upper and lower chamber portions 114 and 94. Piston portion 102 has flrst and second passageways each having one way spring-biased check valves 104, 107 the valve 104 in passageway 103 being arranged to pass fluid from the lower chamber to the upper chamber and the valve 107 in passageway 106 being arranged to pass fluid from the upper chamber to the lower chamber. P-assageway 105 extends longitudinally through a connecting mandrel portion to a port 112 disposed just above a lower piston portion 99. The lower piston portion 99 has a lengthwise extended passageway 101 opening below the piston portion and connected at upper ends to an annular recess 110 in the upper face of the lower piston portion 99. A piston valve 108 is slidably and sealingly received on the connecting mandrel portion between the upper and lower piston portions. Piston valve 108 has a depending annular valve element 111 adapted to seat in the :annular recess 110 and close off the passageways 101 and 106. A spring disposed between the upper piston portion 102 and piston v-alve 108 normally biases the valve ele-ment into the annular valve seat 110 above the passageway 101. The piston valve has an O-ring -seal and in the normal position shown in FIG. 5, the piston valve closes off port 112 from fluid flow. Below upper bore portion 89 of the housing is an enlarged bore portion 88 providing a large bypass space for valve piston 108. Below enlarged bore portion 88 is a valve piston bore portion 89a which is sized relative to the valve piston to provide a restricted or metered annular orifice 113 (FIG. 7) when the valve piston is displaced into the valve piston bore portion 89a. Below valve piston bore portion 89a is a lower piston bore portion 91 which is sized relative to the lower piston portion 99 to provide a restricted annular space therebetween.

In the operation of this embodiment of the invention,

reference is rst made to FIG. 5 where the elements are shown in their respective positions as the tool is being lowered into the well bore before the packer is set. As described heretofore, the mandrel 84 of the safety seal section is connected to the mandrel of the packer and the housing of the safety seal section is connected to the housing of the packer. Thus, the safety seal mandrel will be moved downward relative to the safety seal housing in the setting of the packer -as described heretofore. Thus, as the mandrel section is moved downwardly the packer element 22 mounted :between the flanges on the packer mandrel and housing is expanded. The relative downward movement in the safety seal section causes the mandrel piston assembly 98 to move downwardly in the fluid chamber 87 and produces `a transfer of lluid from the lower fluid chamber portion 94 to the upper fluid chamber portion 114 via passage 103. Fluid also passes through lower piston portion 99 via passage 101 and the resulting fluid pressure unseats the valve element 111 from the valve seat.

In FIG. 6 the mandrel is shown midway of its movement in the housing and the arrows illustrate the direction of fluid flow. After the packer element 22 has been expanded in the casing and the relative movement between the mandrel 84 and housing 86 is stopped, the spring 109 positioned between the upper piston portion 102 of the piston and the valve piston 108 moves the valve piston 108 downwardly into the delay piston bore portion 89a of the housing. The valve element 111, after a period of time, is seated in the valve seat 110 in the lower piston portion 99 (FIG. 7). The valve element 111 also seals off the port 112 of the passageway 106 in the piston assembly. Movement of the valve piston 108 into the bore portion 89a of the housing is delayed by a restricted annular space 113 formed between the piston valve 108 and the Valve bore portion 89. Again, it is apparent that the time required to close the passageway 101 in the lower piston portion 99 and consequently the speed the valve 108 moves in the valve piston -bore 89a is determinable by the size of the restricted space 113 and the force of the spring 109. After the valve element 111 closes passageways 101 and 112, the lower chamber portion 94 is isolated from fluid communication with the upper chamber portion 114. Thus, tools or parts above the packer mandrel can be pulled upwardly (at least for short periods of time) to perform manipulations of other tools in the tool string and will not unseat the packer element 22 from the casing.

In order to release the safety seal apparatus to permit relative movement between the mandrel and housing and release of the packer, a relative short and quickly applied downward movement on the mandrel 84 will produce a large pressure in fluids in the portion of the lower chamber portion 94 below the lower piston portion. This fluid pressure `acts through the passageway 101 and displaces the piston valve 108 (against the bias of the spring 109) from the valve seat 110 on the lower portion 99 of the piston. Movement of valve element 111 also uncovers the port 112 of the bypass passageway 106 formed through the piston to open the lluid communication passageway 106 from the upper chamber portion 114 to the lower chamber portion 94. This bypass passageway 106 facilitates the upward movement of the mandrel with respect Ito the housing by permitting transfer of fluids from the upper chamber portion to the lower chamber portion as the piston portion 102 moves upwardly in the chamber.

While the present invention has been disclosed for use with a packer where it has a particular utility, it should be appreciated that the present invention has other` applications. In essence, the present invention contemplates providing a selectively operable self-contained hydraulic system for releasably retaining telescoping members in one of their expanded or contracted positions. The hydraulic system includes means for trapping fluid in a telescopic 7 portion and means for releasing the trapping means in response to manipulation of the telescopic members.

Additionally, while Iparticular embodiments of the present invention have been shown and described, it is apparent that changes and modilications may be made without departing from this invention in its broader aspects and therefore, the aim in the appended claims is to cover all such changes and modications as fall within the true spirit and scope of this invention.

I claim:

1. A device for controlling movement between telescoping members of a well tool comprising:

means forming a chamber between said telescoping members -for receiving a fluid,

piston means formed on one of said members and slidably received in said chamber,

` said piston means having a passageway formed therein for passing fluid from one part of said chamber to another through said piston,

valve means biased to close said passageway in the absence of relative movement between said members and responsive to an increase in Huid pressure in said passageway to open said passageway, and time delay means for impeding the reclosin-g of said passageway by said valve means in the absence of relative movement between said members.

2. A device for controlling relative movement between telescoping members of a tool comprising:

means forming an annular chamber between said members;

an annular piston -formed on one of said members and rslidably received within said chamber to divide said chamber into upper and lower portions,

a plurality of passageways formed through said piston for providing fluid communication above and below said piston,

a recessed portion formed on said piston with said passageways opening into said recessed portion,

a control valve slidably positioned within said recessed portion of said piston and movable between at least two positions,

means on said Vcontrol valve for closing off lluid communication between said passageways and recessed portion in one of said positions :and for opening said passageways to fluid communication with said recessed portion in the other of said positions, and

means normally urging said control valve to the position where iiuid communication between said passageways and recessed portion is closed but yielding to 'an increase in pressure in one of said cham-ber portions to permit positioning of said control valve under the force of said pressure increase in the other position where said passageways are open to said recessed portion.

3. A device positioned between and for controlling the relative movement of two telescoping members of a well tool comprising:

means forming a Huid chamber between said telescopin g members,

a piston formed on one of said member and slidably received within said chamber to divide said chamber into upper and lower portions,

a rst and second passageway formed through said piston providing a fluid communication path between said upper and lower portions above and below said piston,

control means movably positioned in said piston for controlling fluid ilow through said passageways between the uid chamber portions above and below said piston,

means normally urging said control means into a position for shutting olf fluid flow through said piston between said upper and lower chamber portions,

said control means responsive to a differential pressure across said control means for opening a fluid cornmunication path from one end of said chamber to another, and delay means for rotar-ding the repositioning of said control means for shutting off said fluid flow.

4. A device positioned between and for controlling the relative movement of two telescoping -members of a well tool comprising: means forming a fluid chamber between said telescoping members, a piston formed on one of said mem-bers and slidably received within said chamber to divide said chamber into upper and lower portions, a lirst and second passageway formed through said piston providing a fluid communication path between said upper and lower portions above and below said piston, control means Amovably positioned in said piston for controlling liiuid flow through said passageways between the iluid chamber portions above and below said piston, means normally urging said control means into a position for shutting off uid flow through said piston between said upper and lower chamber portions, said control means responsive to a differential pressure across said control means for opening a uid communication path from one end of said chamber to another, and restricted bypass means in said piston for providing a uid flow path around said piston in the event said control means is not operable.

5. An apparatus for packing olf a well bore comprising:

a pair of telescoping tubular members,

ann expandable packer means positioned on said members for expanding upon relative movement of said members in one direction and contracting upon relative movement of said members in the opposite direction,

means forming a fluid chamber between said members,

a piston formed on one of said members and slidably received within said chamber to divided said chamber into upper and lower portions,

a first passageway formed in said piston for providing a fluid flow path from said lower portion to said upper portion,

a second passageway formed in said piston for providing a fluid ow path from said upper portion to said lower portion,

control means movably positioned on said piston,

said control means operable upon movement for opening and closing at least one of said passageways to lluid communication between said upper and lower portions,

means forming a part of said control means for permitting a restricted fluid flow around said control means,

means effective upon the absence of relative movement between said members for urging said control means into one of said positions to close at least one of said passageways, and

means responsive to an increase in pressure in one of said chamber portions to force said control means to another position to open said passageways to fluid communication,

said control means maintaining said passageways open for a time period determina-ble by the amount of restricted fluid tiow around said control means.

6. An apparatus for packing olf a well bore comprising:

a pair of telescoping tubular members,

an expandable packer means positioned on said members for expanding upon relative movement of said members in one direction and for contracting upon relative movement of said members in the opposite direction,

means forming a chamber between said telescoping members for receiving a iluid,

piston means formed on one of said members and slidably received in said chamber,

said piston means havin-g a passageway formed therein for passing Huid from one part of said chamber to another through said piston, and

valve means biased to close said passageway in the absence of relative movement between said members and responsive to a relative movement between said members tending to expand said packer means to open said passageway.

7. An apparatus for packing off a well bore comprising a pair of telescoping tubular members,

an expandable packer means positioned on said members for expanding upon relative movement of said members in one direction and contracting upon relative movement of said members in the opposite direction,

means forming a chamber between said telescoping members for receiving a uid,

piston means formed on one of said members and slidably received in said chamber,

said piston means having a passageway formed therein for passing fluid from one part of said chamber to another through said piston, and

valve means biased to close said passageway in the absence of relative movement between said members and responsive to an increase in iiuid pressure in said passageway to open said passageway, and

restricted bypass means in said valve means for providing a fluid ilow path around said valve .means in the event said valve means is inoperative.

8. A device positioned between and for controlling the relative movement of two telescopin-g members of a well tool in a well bore comprising:

means forming a Huid chamber between said telescopin g members,

seal means on one of said members for sealing one end of said chamber,

a compensating piston with sealin-g means thereon positioned at the other end of said chamber for sealing the other end of said chamber and for providing volume compensation to said chamber upon temperature changes encountered in said well bore,

a piston formed on one of said members and slidably received within said chamber to divide said chamber into upper and lower portions,

a first and second passageway formed through said piston providing a fluid communication path between said upper and lower portions above and below said piston,

control means movably positioned in said piston for controlling fluid iiow through said passageways between the fluid chamber portions above and below said piston,

means normally urging said control means into a position for shutting off iiuid iiow through said piston between said upper and lower chamber portions,

said control means being responsive to a differential pressure across said control means for opening a uid communication path from one end of said chamber to another, and delay means for retarding the repositioning of said control means for shutting off said uid flow.

9. A device for controlling movement between telescoping members of a well tool comprising:

means forming a chamber between said telescoping members for receiving a fluid,

piston means formed on one of said members and slidably received in said chamber,

said piston means having two enlarged portions therea passageway formed through one of said portions for providing a fluid communication path above and below said portion,

a pair of passageways in the other portion each having means for permitting fluid flow in only one direction with one passageway permitting flow opposite to the other,

valve means movably positioned on said piston between said enlarged portions, and

means effective in the absence of relative movement 'between said telescoping members for urging said valve means into a position to close said passageway on said one portion and at the same time to close one of said passageways on the other portion of said piston,

said valve means moving to another position in response to a differential pressure across said one portion to open said pssageways.

References Cited bythe Examiner UNITED STATES PATENTS Re. 24,352 8/1957 Comstock 166-145 2,645,459 7/ 1953 Sutlii 175-297 2,901,001 8/1959 Nutter 166-152 X 2,942,669 6/ 1960 Mounce et al 166-226 X 2,951,539 9/1960 Malone et al 166-266 X 3,043,373 7/1962 Chenault 175-297 JACOB L. NACKENOFF, Primary Examiner.A

CHARLES E. OCONNELL, Examiner.

D. H. BROWN, Assistant Examiner. 

1. A DEVICE FOR CONTROLLING MOVEMENT BETWEEN TELESCOPING MEMBERS OF A WELL TOOL COMPRISING: MEANS FORMING A CHAMBER BETWEEN SAID TELESCOPING MEMBERS FOR RECEIVING A FLUID, PISTON MEANS FORMED ON ONE OF SAID MEMBERS AND SLIDABLY RECEIVED IN SAID CHAMBER, SAID PISTON MEANS HAVING A PASSAGEWAY FORMED THEREIN FOR PASSING FLUID FROM ONE PART OF SAID CHAMBER TO ANOTHER THROUGH SAID PISTON, VALVE MEANS BIASED TO CLOSE SAID PASSAGEWAY IN THE ABSENCE OF RELATIVE MOVEMENT BETWEEN SAID MEMBERS AND RESPONSIVE TO AN INCREASE IN FLUID PRESSURE IN SAID PASSAGEWAY TO OPEN SAID PASSAGEWAY, AND TIME DELAY MEANS FOR IMPEDING THE RECLOSING OF SAID PASSAGEWAY BY SAID VALVE MEANS IN THE ABSENCE OF RELATIVE MOVEMENT BETWEEN SAID MEMBERS. 